Why ground from the negative terminal?

[CL8]

what is the reason auto makers switched from grounding the positive battery terminal, to grounding the negative terminal?

Also does grounding serve any other purpose than to give the electric current a path to travel?

Thanks, cl8

[curtis73]

It was primarily a marketing move. I think DeSoto was the first to go negative ground because most people thought that DC electricity flowed from positive to negative even though it doesn't.

Either way, it doesn't matter. electricity flows regardless of which one is the ground. The idea of having a ground is so you don't have to run heavy wires all over the place. Just use the metal of the vehicle to be the conductor for one side of the battery.

[CL8]

Thanks Curtis

[CL8]

I was recently talking with someone from Australia who told me electrons go from the positive side to the negative side on a battery.

In the southern hemisphere do electrons flow in the opposite direction, like water does going down a drain?

[j cAT]

Originally Posted by CL8

I was recently talking with someone from Australia who told me electrons go from the positive side to the negative side on a battery.

In the southern hemisphere do electrons flow in the opposite direction, like water does going down a drain?

electrons flow from negitive to positive even on mars...
as long as the polarity is correct , this is not an issue..

positive or neg grounding is not very important...as long as it is not reversed.....

[CL8]

Thanks jcat, the guy came back and admitted he was wrong.
What do you mean by "reversing" the grounding?

If you ungrounded the negative then grounded the positive, would it damage the electrical system?

I'm originally from EVERETT Washington!

[curtis73]

You would have to switch wires on everything. Like for instance, your radio would have to ground the red wire and hook up the black wire to a negative sourced wire. If you simply reversed the battery cables, you would send electricity backwards through all the accessories. That's fine for simple things like lights that don't care, but things like computers, alternators, some types of relays, diodes, etc, it won't work. It would be a massive undertaking with a complete custom wiring harness and a LOT of logically re-engineering and thinking. But it can be done.

[j cAT]

Originally Posted by j cAT

electrons flow from negitive to positive even on mars...
as long as the polarity is correct , this is not an issue..

positive or neg grounding is not very important...as long as it is not reversed.....

the oem design must not be reversed as this would cause the vehicles operating electrical system to be damaged...

one example is on relays you have diodes..these devices prevent reverse voltage spikes when the relay de-energizes...these would be damaged..

most pcm/computers on vehicles fail because of poor grounds that then allow these reverse voltages to damage the internal componets.

everett ma is a small city directly on the northern border of boston..

[maxwedge]

Ford and Chrysler were negative gd till 55-56, when they went to 12V.

[CL8]

Originally Posted by j cAT

the oem design must not be reversed as this would cause the vehicles operating electrical system to be damaged...

one example is on relays you have diodes..these devices prevent reverse voltage spikes when the relay de-energizes...these would be damaged..

most pcm/computers on vehicles fail because of poor grounds that then allow these reverse voltages to damage the internal componets.

everett ma is a small city directly on the northern border of boston..

So you're saying if someone rewired everything as Curtis said (I've read of people doing this), that would damage the electrical system?

Ford and Chrysler were negative gd till 55-56, when they went to 12V.

From my research all auto manufacturers have negative grounding now to standardize the system.

[Moppie]

Originally Posted by CL8

From my research all auto manufacturers have negative grounding now to standardize the system.

Most of the electrical (I think you could even say all) parts in your car are made by a variety of 3rd party manufactorers.
This is why things became standardised.
I think you will find that most of the parts manufactorers started using a negative earth because that is a general standard in electrial engineering.

[j cAT]

Originally Posted by CL8

So you're saying if someone rewired everything as Curtis said (I've read of people doing this), that would damage the electrical system?
From my research all auto manufacturers have negative grounding now to standardize the system.

exactly,,,,don't even think of it...the vehicles made today are too complicated with all the electronic devices that must have a smooth direct current voltage of the proper polarity,,,,no voltage spikes or it will mean electronic failures..

vehicles made before 1975 it is possible to do,,,but why ???

when a vehicle ages these body/frame grounds fail...then you have all kinds of weird intermittent problems...with all the metal rusted and corroded..

[CL8]

Thanks for the advice jcat!

Does anyone know how long it would take for corrosion build up on a battery to destroy it so it doesn't hold a charge?

Thanks, cl8